1. Field of the Invention
The present invention relates to a needle holder used for surgery in which tissue is sutured by using a circular arc-like needle, and in particular, relates to a needle holder suitable to endoscopic surgery.
2. Description of the Related Art
When tissue is sutured in surgery, a needle holder 100 as illustrated in FIG. 12A is used in general. The needle holder 100 has a configuration in which a pair of shafts 101 having gripping portions 102 provided at one ends and handle portions 103 provided at the other ends are pivotally fitted to each other in a rotationally movable manner about an axis 105 like scissors. The pair of gripping portions 102 are opened and closed with opening/closing operations of the handle portions 103. With this, a needle can be held between gripping surfaces 104 of the pair of gripping portions 102, which are opposed to each other. When a circular arc-like needle is gripped with such needle holder 100 to suture tissue, a direction of a needle 97 is changed by inclining axial directions (S) of the shafts with respect to a tissue 98 to be sutured as illustrated in FIG. 12C from a state where one end of the needle 97 is thrust into the tissue 98 as illustrated in FIG. 12B so that the needle 97 is made to penetrate through the tissue 98.
The endoscopic surgery is performed by inserting an instrument with an elongated thin handle and an endoscope into a cannula guided by a dilator or a trocar. For example, as illustrated in FIG. 14, a gripping forceps 110 for common endoscopic surgery has a pair of jaw portions 112 provided at a front end of an elongated shaft 111. The pair of jaw portions 112 can be opened and closed by operating a handle 113 provided at a base end side. Such an instrument for endoscopic surgery is used in a state of being inserted into an elongated cylindrical cannula 95. Therefore, motions of the instrument are inevitably limited. To be more specific, motions allowed for the instrument are substantially limited to a rotating motion (R direction in FIG. 14) about an axial core of the shaft 111 and a linear motion (forward/backward motions, Z direction in FIG. 14) along an axial direction of the shaft 111 except for motions unique to the instrument such as motions of the jaw portions 112 in the gripping forceps 110.
Therefore, when tissue is sutured endoscopically by gripping a needle with an instrument for endoscopic surgery, such as a gripping forceps, the axial direction of a shaft cannot be inclined unlike a usage method of the needle holder 100 as described above with reference to FIG. 12B and FIG. 12C. Accordingly, tissue cannot be sutured with a conventional instrument for endoscopic surgery. For example, in lumbar endoscope surgery, there are quite a few cases that dura mater injury is generated incidentally. Dura mater is injured in a splitting manner in a fiber direction. Therefore, as illustrated in FIG. 14, a dura mater injury 99 is generated in a direction (direction indicated by a line X in FIG. 14) intersecting with an axial direction of the cannula 95 (axial direction of the shaft 111).
In order to suture the injury generated in the above direction with a circular arc-like needle, the following operations need to be performed. That is, as illustrated in FIG. 13A, the needle 97 is inclined such that a front end thereof moves toward an inner portion of the tissue 98, and the end of the needle 97 is thrust into the tissue. Thereafter, as illustrated in FIG. 13B, the needle 97 is rotationally moved in a circumferential direction so that the front end of the needle 97 is made to exit to an outer side of a surface of the tissue 98. It is to be noted that in FIG. 13B, a state where the needle 97 is rotationally moved in the circumferential direction about a center point C of a circular arc. However, in actual suture surgery, when a needle is rotationally moved in a circumferential direction, the needle is not required to be rotationally moved about a center point of a circular arc accurately. In the specification, an expression “a circular arc-like needle is rotationally moved in a circumferential direction” is used including a case where a center point of an circular arc is slightly deviated between before and after the needle is rotationally moved.
However, in a conventional gripping forceps, even if the needle 97 is gripped such that the front end of the needle 97 moves toward the inner portion of the tissue 98 as illustrated in FIG. 13A, an axial direction (S1) of a shaft of the gripping forceps cannot be inclined in a state where the needle 97 is inserted into an elongated cannula. Therefore, in the conventional gripping forceps, the needle 97 cannot be rotationally moved in the circumferential direction in the above state. Accordingly, under the present circumstances, when an injury is generated in the direction that the injury cannot be sutured unless the needle 97 is rotationally moved in the circumferential direction as described above, the injury is sutured in the following manner. That is, in the above case, endoscopic surgery is stopped, a body surface is largely incised and the injury is sutured under direct vision or microscopically.
As a needle holder intended for inclining a circular arc-like needle, a needle holder in which a pair of needle holding pieces 121 are assembled in a scissors-like form as illustrated in FIGS. 15A to 15D has been proposed (see, Japanese Patent Application Laid-open No. 2007-54249). To be more specific, a gripping portion 122 having a perpendicular gripping surface 124 is attached to a front end of each needle holding piece 121 in a rotationally movable manner in the needle holder. The needle holder has a configuration in which each of a pair of gripping portions 122 rotates about an axial core 125 of itself so as to incline the needle 97. Therefore, the circular arc-like needle 97 cannot be rotated in the circumferential direction. It is to be noted that FIG. 15A and FIG. 15B illustrate a state before the pair of gripping portions 122 are rotated about the axial cores 125, and FIG. 15C and FIG. 15D illustrate a state after the pair of gripping portions 122 are rotated about the axial cores 125.
In addition, an instrument for endoscopic surgery needs to be reduced in size for being inserted into a cannula having a small diameter. However, the needle holder as disclosed in Japanese Patent Application Laid-open No. 2007-54249 is difficult to be reduced in size because the needle holder has a complicated configuration in which the pair of gripping portions 122 which are rotatable about the axial cores 125 are provided at front ends.